Rotodynamic pumps are characterized in general by having a casing in which an impeller is positioned for rotation. The pump casing includes an inlet through which fluid enters the pump, and a discharge outlet through which fluid is discharged.
The impeller is operatively connected to a drive shaft that is rotationally driven by a motor which, in turn, imparts rotation to the impeller. The impeller is typically sealed from the casing by mechanical seal means that prevent fluid leakage from about the impeller and/or drive shaft and the pump casing.
The drive shaft is typically supported by a series of bearings that may have any number and type of constructions or configurations. The drive shaft typically extends through a bearing housing or support, which is structured to also maintain the bearings through which the drive shaft passes.
It is well known that the mechanical seals and bearings become heated from the friction induced by the rotation of the drive shaft and impeller relative to the bearings and seals. Therefore, it is necessary to keep the seals and bearings lubricated and cooled. This is conventionally accomplished by providing a coolant and/or lubricant to the bearings and seals, which can be accomplished in a variety of ways. For example, the bearings may conventionally be pre-packed with grease, and/or grease can be delivered through external ports in a bearing housing to keep the bearings lubricated.